The Electric Boat Corporation[1] ((EB) is a division of General Dynamics Corporation. It has been the primary builder of submarines for the United States Navy for well over 100 years.
The company's main facilities are a shipyard in Groton, Connecticut and a hull-fabrication and outfitting facility in Quonset Point, Rhode Island.
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The company was founded in 1899 by Isaac Rice as the Electric Boat Company in order to build to completion John Philip Holland's submersible designs which were developed at Lewis Nixon's Crescent Shipyard, located in Elizabeth, New Jersey, USA. The first submarine that this shipyard built was (originally) named the Holland VI, later to be known as USS Holland [SS-1]. This was the first submarine to be purchased and commissioned into United States naval service on 11 April 1900. The success of Holland VI ushered in the demand for follow up models (A-class) that began with the proto-type submersible "Fulton" built at the same shipyard where Holland was conceived. Many foreign governments were soon interested in John Holland's latest submarine designs and began purchasing the rights to build them under licensing contracts through Isaac Rice's Electric Boat Company. These governments included Great Britain, Royal Navy; Japan, Imperial Japanese Navy; Russia, Imperial Russian Navy, the Netherlands, Royal Netherlands Navy; and other "civilized" countries.
These new weapons initially devised and developed by the Holland Torpedo Boat Company were now legitimized as genuine naval weapons by the world's most modern industrialized nations during the early part of the 1900s. They were meant to abide by the Hague Conventions of 1899 and 1907, see submarine warfare, but during World War I Germany adopted unrestricted submarine warfare.
During World War I, the company and its subsidiaries built 85 submarines and 722 submarine chasers for the U.S. Navy. After the war the Navy did not order another submarine until 1934. In World War II, the company built 74 submarines.
The firm renamed itself to General Dynamics Corporation in 1952, and when Convair was acquired the next year, the holding company assumed the "General Dynamics" name, with the submarine building operation retaining the "Electric Boat" name. [2]
Electric Boat built the first nuclear submarine, USS Nautilus, which was launched in January 1954, and the first ballistic-missile submarine, George Washington, in 1959, amongst others. Submarines of the Ohio-, Los Angeles-, Seawolf- and Virginia-class submarines were also constructed by Electric Boat.
In 2002, Electric Boat conducted preservation work on the world's first nuclear powered craft, USS Nautilus, preparing her for her berth at the U.S. Navy Submarine Force Museum and Library in Groton, Connecticut, where she now resides as a museum. Electric Boat's first submarine, the USS Holland was unfortunately scrapped for one hundred dollars in 1913.
Electric Boat is also in the business of performing overhaul and repair work on fast attack class boats. Ships that are already built return to Electric Boat's Graving Docks for needed repairs. Electric Boat built the Ohio class fleet ballistic missile submarines and Seawolf class (SSN 21) attack submarines as well as others. However, most of the work done in the ship yard is focused on the new construction of Virginia-class attack submarines.
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While most boats on the water today are powered by diesel engines, and sail power and gasoline engines are also popular, it is perfectly feasible to power boats by electricity too.
Electric boats were very popular from the 1880s[citation needed] until the 1920s, when the internal combustion engine took dominance. Since the energy crises of the 1970s, interest in this quiet and potentially renewable marine energy source has been increasing steadily again, especially as solar cells became available, for the first time making possible motorboats with an infinite range like sailboats. The first practical solar boat was probably constructed in 1975 in England.[1]
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The main components of the drive system of any electrically powered boat are similar in all cases, and similar to the options available for any electric vehicle.
Electric energy has to be obtained for the battery bank from some source.
In all cases, a charge regulator is needed. This ensures that the batteries are charged at the maximum rate that they safely can stand when the power is available. It also ensures that they are not overcharged when nearing full charge and not overheated when a large charge current becomes available.
There have been significant technical advances in battery technology in recent years, and more are to be expected in the future.
The size of the battery bank determines the range of the boat under electric power alone. The speed that the boat is motored at also affects this - a lower speed can make a big difference to the energy required to move a hull. Other factors that affect range include sea-state, windage and any charge that can be reclaimed while under way, for example by solar panels in full sun. A wind tubine in a good following wind will help, and motor-sailing in any wind could do so even more.
To make the boat usable and maneuverable, a simple-to-operate forward/stop/backwards speed controller is needed. This must be efficient—i.e. it must not get hot and waste energy at any speed—and it must be able to stand the full current that could conceivably flow under any full-load condition. One of the most common types of speed controllers uses Pulse-width modulation (PWM). PWM controllers send high frequency pulses of power to the motor(s). As more power is needed the pulses become longer in duration.
A wide variety of electric motor technologies are in use. Traditional field-wound DC motors were and still are used. Today many boats use lightweight permanent magnet DC motors. The advantage of both types is that while the speed can be controlled electronically, this is not a requirement. Some boats use AC motors or permanent magnet brushless motors. The advantages of these are the lack of commutators which can wear out or fail and the often lower currents allowing thinner cables; the disadvantages are the total reliance on the required electronic controllers and the usually high voltages which require a high standard of insulation.
Traditional boats use an inboard motor powering a propeller though a propeller shaft complete with bearings and seals. Often a gear reduction is incorporated in order to be able to use a larger more efficient propeller. This can be a traditional gear box, coaxial planetary gears or a transmission with belts or chains. Because of the inevitable loss associated with gearing, many drives eliminate it by using slow high-torque motors. The electric motor can be encapsulated into a pod with the propeller and fixed outside the hull (saildrive) or on an outboard fixture (outboard motor).
There are as many types of electric boat as there are boats with any other method of propulsion, but some types are significant for various reasons.
cruising on the Untersee, a part of Lake Constance. It is based in Radolfzell, Germany.]]
All the component parts of any boat have to be manufactured and will eventually have to be disposed of. Some pollution and use of other energy sources are inevitable during these stages of the boat's life and electric boats are no exception. The benefits to the global environment that are achieved by the use of electric propulsion are manifested during the working life of the boat, which can be many years. These benefits are also most directly felt in the sensitive and very beautiful environments in which such a boat is used.
Japan's biggest shipping line Nippon Yusen KK and Nippon Oil Corporation said solar panels capable of generating 40 kilowatts of electricity would be placed on top of a 60,000 tonne car carrier ship to be used by Toyota Motor Corporation.[5][6][7]
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